Short-wave aerial



1942. FEUSSNER ET-AL 2,293,429

\SHORT WAVE AERIAL Filed May 16, 1941 INVENTORS HELLMUTl-l FEUSSNERATTORNEY Patented Aug. 18, 1942 UNITED STATES PATENT OFFICE SHORT-WAVEAERIAL Application May 16, 1941, Serial No. 393,708 In Germany February9, 1940 3 Claims.

In transmitter and receiver apparatus ofradio signaling work operatingwith short waves unsupported antenna are employed. The latter for anumber of special uses must be flexible in order that they may be laidor folded together to result in relatively reduced dimensions. They mustmoreover be elastic in order that by being bent they may not lose theirshape. Finally, they must possess adequate mechanical damping in orderthat their period of vibration may not be long. For this purpose,antennae consisting of solid metal have been suggested of a formtapering from the base or bottom end to the end or top thus resulting ina conical form. However, antennae of this kind inhere the drawback thatthey possess relatively little mechanical damping and that the materialis subjected to marked bending stresses on folding the antenna.

According to this invention an antenna tapered toward the top is made byusing a plurality of wires of like diameter, but dissimilar length, thewires being united in such a way that the number of adjacent wires,figured from the bottom or base up to the top of the antenna diminishes,

securing to one another of the Wires being such that upon fiexure of theantenna slight displacement or shift of the constituent wires in anaxial direction is possible.

An antenna, according to the invention, is shown in the drawing whereinFigure 1 is an elevation and Figure 2 is an end view. As can be seenthis antenna consists of a plurality of equal, constituent wires, I, 2,3, 4, 5, etc., which are disposed around the longest wire, although itis possible also to use several wires having the aggregate length of theantenna. The top ends of each constituent wire surrounding the centerwire consists of eyelets B, l, 8, 9 through which the longer wires arethreaded and held together. At the bottom or base end all of the wiresare inter-connected by any convenient means, not shown. Thisconstruction offers the advantage that as a result of subdivision and ofthe change of the constituents being able to shift in respect to oneanother, the stress in the material arising upon bending the antennawill be less than in the case where the aerial of similar form is madeof solid metal. The friction between the constituent wires in respect toone another considerably raises the mechanical damping of the antenna sothat the time-constant for mechanical vibrations becomes small. It couldbe surmised that the mutual contact between the constituent wires of thebunch might occasion crackling noises in radio apparatus. However, thishas not been observed to be the case, for, as a matter of fact,neighboring portions of the constituent wires are always at one and thesame potential. What should also be mentioned in this connection is thisfurther advantage that the construction of the antenna of the inventionis simple and of low cost. It will also be understood that the inventionis not restricted to the exemplified embodiment here shown. Theelementary Wires, furthermore, need not be of circular cross-sectionalform; in fact, they could also consist of ribbons or bands and have anydesired or convenient cross-sectional shape.

We claim:

1. An antenna comprising a bundle of parallel elastic conductive rods ofdissimilar lengths, all of said rods having their one ends in alignmentand means surrounding said bundle and clamping said rods together at theother ends of said rods.

2. An antenna comprising a bundle of parallel elastic conductive rods ofdissimilar lengths, all of said rods having their one ends in alignmentand means surrounding said bundle and clamping said rods together at theother ends of all of said rods except the longest.

3. An antenna comprising a. bundle of parallel elastic conductive rodsof dissimilar lengths, all of

